Fuel systems for motor vehicles are known to include a fuel tank and a filler tube having an inlet through which fuel is dispensed into the tank. It is known to use a removable cap at the end of the filler tube to close the tube. It is known also to use a movable damper and a rubber seal to close the fuel system either as the primary shutoff valve or as a secondary, supplemental shut-off structure. Capless refueling systems are known, wherein a screw-on cap is not required, and the act of inserting a filler nozzle opens the inlet end of the tube for filling by moving a stopper that closes the end of the tube.
The filler tube inlet, whether of a capless or capped design, is known to be contained within a housing that surrounds the inlet, forming a boxlike area around the inlet. An external door is provided on the housing, and can be opened and closed to provide access to the filler tube inlet. The door is a multi-piece assembly that has an exterior ornamental outer door panel snap fit to a supporting structure forming the hinge. The ornamental outer structure complements the exterior surface of the vehicle body to provide an aesthetically pleasing appearance. It is not uncommon for a gap to exist between the fuel housing door panel and the mating housing structure. As a result, debris such as water, dirt, ice and the like may find its way into the fuel housing boxed in area around the filler tube inlet. The cap or other closure at the end of the filler tube inlet prevents the contaminant material from entering the filler tube so that vehicle operation is not adversely affected from contaminants in the fuel.
In a capped fuel system inlet, the cap is designed to keep contaminants away from the inlet end of the filler tube, and the act of removing the cap moves any debris that has accumulated on the cap away from the inlet area. Accordingly, a refueling nozzle can be inserted into the filler tube without carrying significant debris or contaminants with it. However, capless refueling systems are gaining acceptance to simplify and speed up refueling operations, and to eliminate the need for vehicle operators to handle a dirty fuel cap during a refueling operation. A disadvantage of not having a cap is that contaminants that enter the housing area can accumulate on the end of the filler tube inlet, specifically on the outer surface of the sliding structures that are moved out of the way when a refueling nozzle is inserted. In a capless design, contaminants are prevented from entering the inlet nozzle during normal vehicle operation, but can be pushed into the inlet tube by the filler nozzle when the nozzle is inserted for refueling. Attempts to seal the door panel against the housing structure have not been effective in that the sealing relationship is difficult to establish and maintain and can make the access door difficult to open.
What is needed in the art is structure to effectively seal and protect a fuel system refueling housing from intrusion of contaminants without making the access door of the housing difficult to operate.